Online reviews wield almost limitless power in the travel business. Go up one point on Travelocity or other online review sites and you could raise rates by more than 10 percent. However, just one negative review has been seen to have more influence than 100 positive reviews. Our digital expert Phil Baker shares what to pay attention to and what to ignore when reading online reviews.

Review sites offer a tremendous benefit to us as consumers. Whether it’s a restaurant, an electrician, or a product, learning from others’ experiences does help us make a better, more informed choice. But, it also has a high potential for abuse. On many sites, anyone can post an opinion, even those with ulterior motives.

In a recent court ruling, a Virginia cleaning business successfully sued Yelp, forcing them to provide the identity of reviewers who had provided disparaging remarks. The business owner had requested the names of the reviewers to determine if they were real customers. The court ruled that the reviewers were not protected by freedom of speech laws if it could be proven that they were not customers of the business. This is a potentially significant case for review sites, and one that could protect companies from false claims made by competitors or others seeking revenge.

One of the biggest issues businesses have with Yelp is that it ignores requests to remove what they consider to be false reviews.

Yelp has no effective mechanism to do so and rarely responds to complaints, based on scores of complaints leveled at Yelp on its own site. With the power that some rating sites have on the viability of a business, it’s no wonder that businesses are so sensitive to false reviews. It’s one thing to get a bad review from a customer, but not from a disgruntled employee, a customer taking revenge, or a competitor.

A single one-star review could significantly lower the overall rating of a business. When a business can’t remove a false review, its only recourse is to try to balance it with a positive review, further corrupting the rating system. I usually ignore those reviews at the extremes, particularly if they are petty or not well-written. But, when making a choice between several businesses, the natural instinct is to pick the one with the highest rating.

When looking for a review site, opt for verified reviews as opposed to open reviews. Open reviews can be posted by anyone, but verified reviews can only be posted after a confirmed booking.The impact of a few negative reviews is not limited to Yelp. I recently heard from the owner of a touring company about the impact that a single negative review had on his business. While the owner requested that I not divulge his name, I have used his company many times, and it is adored by its customers. Let’s call him Ted. Ted’s company holds an excellent rating on TripAdvisor; 99.5 percent of the reviews are five stars, and the others are four stars. The company is the No. 1 listing in its area of tourism.

In fact, much of Ted’s success has come from his high ratings and exposure on TripAdvisor. (That’s how my wife found the company). The company is rated No. 1 for its city, No. 1 for its province, No. 1 for its region, and No. 3 for the entire country.

It’s natural for anyone searching to immediately go to a business with so many No. 1 ratings, but that also makes a business vulnerable to a bad rating, and that’s what happened. One day a negative review appeared that Ted later found to be written by a disgruntled employee.

TripAdvisor allows a company to post a public response, so Ted wrote a diplomatic response that countered the review’s contents. You would think that people would then ignore the bad review and not allow it to color their opinion of the company. Not so.

“Nearly every phone call or email we received from potential guests included the line ‘I saw all the wonderful reviews, and while you wrote a wonderful response, I am concerned about the negative review I read,’” Ted told me. “Although about 100 people said this was the best experience of their entire life, and only one person had something negative to say, potential customers were concerned because of the one.”

For Ted’s company, this one negative review had more power than 100 positive reviews. The day after the review was posted, the company’s ranking plunged so far that it was no longer visible on any list, nor did it appear on the first page of any search. One day No. 1 and the next day gone.

Fortunately, TripAdvisor has a process so businesses can contest a bad review. It took several months to complete the investigation and the review was eventually removed, but it cost Ted’s business hundreds of thousands of dollars of lost revenues. TripAdvisor assumes the reviewer is correct, and relies on the business to prove otherwise, and that’s not always possible to do. In the case of someone threatening to blackmail you by posting a false review, TripAdvisor has two key requirements. First, you need documented proof. Second, you must submit a report to TripAdvisor before the review is posted.

Eventually, Ted’s company was restored to its original top spot, but at a high cost.

Because these sites are so widely used and have such a big impact, there needs to be a way to prevent rogue reviewers from damaging a business. I would recommend that, if a one-star review is posted and the business files a complaint, the reviewer should be required to provide proof that he actually was a customer by submitting a receipt and specific details of the occurrence. Not only would this provide a quicker resolution for the business, but it would also improve the reliability of the ratings and discourage fake reviews. As for those businesses that deserve the bad ratings, such a policy would make them more credible.

Consumers, read between the lines when evaluating both fake and positive reviews. Trust your gut. If a negative review seems vindictive, temper your concerns. If you see several reviews posted within a short period, it’s a red flag, and watch out for aggressively positive reviews. Superlative words like “best,” “lushest,” and “superb” are a dead giveaway.